In one typical implementation, an Internet-based video streaming service is offered over the HTTP protocol. As the quality of service of the Internet as a transport network is substantially “best effort”, protocols have been devised that take advantage to the maximal extent of the bandwidth available between a server and a client at any given time, by dynamically switching between different levels of video quality for the streamed content. HTTP adaptive streaming is an example.
Accordingly, at a time when the available bandwidth is high, for instance due to a decreased level of overall network traffic, it is advantageous to stream video encoded at a relatively high quality, representing graphics with a high data rate and/or resolution and/or a high frame rate. Similarly, at a time when the available bandwidth is low, for instance due to an increased level of overall network traffic, it is advantageous to stream video encoded at a relatively low data rate, representing graphics with a low resolution and/or a low frame rate.
HTTP Adaptive streaming (HAS) is an emerging technique for the delivery of video. It is supported by industry leaders such as Microsoft (Smooth-streaming) and Apple (Live-streaming). One of the advantages of HAS lies in the fact that the existing infrastructure for HTTP web-content (including HTTP servers and proxies, CDNs, . . . ) can be reused for video distribution.
Despite the growing popularity of HAS as a novel, improved video delivery solution, it is currently impossible for providers (content-provider, ISPs, CDN-provider) to track the delivered quality to the consumer.